05-31-2020, 11:31 PM
It's a very common problem. Most commercial printers (that is, consumer version, not magazines, etc.) use sRGB which is what Gimp uses. I find that if I turn my monitor brightness way down and set the gamut up a little, plus lighten the image in Gimp it works pretty well--and even then some images still print too dark. You need to get the ICC profile code for the printer you will be using and add it in Edit>Preferences>Color Management>Soft Proofing add your monitor and the ICC profile for the printer. The soft-proofed image will be more or less what the print will look like--except, as above, if your monitor is too bright it will be dark. Do a sample test and then adjust acordingly.